The contrast between Atlantic and Pacific surface water fluxes
The Atlantic Ocean is known to have higher sea surface salinity than the Pacific Ocean at all latitudes. This is thought to be associated with the Atlantic Meridional Overturning Circulation and deep water formation in the high latitude North Atlantic – a phenomenon not present anywhere in the Pacif...
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ftdoajarticles:oai:doaj.org/article:2a4b20a685554343a2c9a228915eaf81 2023-05-15T17:35:46+02:00 The contrast between Atlantic and Pacific surface water fluxes Philip M. Craig David Ferreira John Methven 2017-01-01T00:00:00Z https://doi.org/10.1080/16000870.2017.1330454 https://doaj.org/article/2a4b20a685554343a2c9a228915eaf81 EN eng Stockholm University Press http://dx.doi.org/10.1080/16000870.2017.1330454 https://doaj.org/toc/1600-0870 1600-0870 doi:10.1080/16000870.2017.1330454 https://doaj.org/article/2a4b20a685554343a2c9a228915eaf81 Tellus: Series A, Dynamic Meteorology and Oceanography, Vol 69, Iss 1 (2017) evaporation precipitation run-off moisture flux salinity freshwater transport Meridional Overturning Circulation Oceanography GC1-1581 Meteorology. Climatology QC851-999 article 2017 ftdoajarticles https://doi.org/10.1080/16000870.2017.1330454 2022-12-31T02:19:00Z The Atlantic Ocean is known to have higher sea surface salinity than the Pacific Ocean at all latitudes. This is thought to be associated with the Atlantic Meridional Overturning Circulation and deep water formation in the high latitude North Atlantic – a phenomenon not present anywhere in the Pacific. This asymmetry may be a result of salt transport in the ocean or an asymmetry in the surface water flux (evaporation minus precipitation; $ E-P $) with greater $ E-P $ over the Atlantic than the Pacific. In this paper, we focus on the surface water flux. Seven estimates of the net freshwater flux ($ E-P-R $ including run-off, R), calculated with different methods and a range of data sources (atmospheric and oceanic reanalyses, surface flux data-sets, hydrographic sections), are compared. It is shown that $ E-P-R $ over the Atlantic is consistently greater than $ E-P-R $ over the Pacific by about 0.4 Sv (1 Sv $ \equiv 10^6\; $m$ ^3 $ s$ ^{-1} $). The Atlantic/Pacific $ E-P-R $ asymmetry is found at all latitudes between 30$ ^\circ $S and 60$ ^\circ $N. Further analysis with ERA-Interim combined with a run-off data-set demonstrates that the basin $ E-P-R $ asymmetry is dominated by an evaporation asymmetry in the northern high-latitudes, but by a precipitation asymmetry everywhere south of 30$ ^\circ $N. At the basin scale, the excess of precipitation over the Pacific compared to the Atlantic ($ \sim 30^\circ $S $ - 60^\circ $N) dominates the asymmetry. Also it is shown that the asymmetry is present throughout the year and quite steady from year to year. Investigation of the interannual variability and trends suggest that the precipitation trends are not robust between data-sets and are indistinguishable from variability. However, a positive trend in evaporation (comparable to other published estimates) is seen in ERA-Interim, consistent with sea surface temperature increases. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Pacific Tellus A: Dynamic Meteorology and Oceanography 69 1 1330454 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
evaporation precipitation run-off moisture flux salinity freshwater transport Meridional Overturning Circulation Oceanography GC1-1581 Meteorology. Climatology QC851-999 |
spellingShingle |
evaporation precipitation run-off moisture flux salinity freshwater transport Meridional Overturning Circulation Oceanography GC1-1581 Meteorology. Climatology QC851-999 Philip M. Craig David Ferreira John Methven The contrast between Atlantic and Pacific surface water fluxes |
topic_facet |
evaporation precipitation run-off moisture flux salinity freshwater transport Meridional Overturning Circulation Oceanography GC1-1581 Meteorology. Climatology QC851-999 |
description |
The Atlantic Ocean is known to have higher sea surface salinity than the Pacific Ocean at all latitudes. This is thought to be associated with the Atlantic Meridional Overturning Circulation and deep water formation in the high latitude North Atlantic – a phenomenon not present anywhere in the Pacific. This asymmetry may be a result of salt transport in the ocean or an asymmetry in the surface water flux (evaporation minus precipitation; $ E-P $) with greater $ E-P $ over the Atlantic than the Pacific. In this paper, we focus on the surface water flux. Seven estimates of the net freshwater flux ($ E-P-R $ including run-off, R), calculated with different methods and a range of data sources (atmospheric and oceanic reanalyses, surface flux data-sets, hydrographic sections), are compared. It is shown that $ E-P-R $ over the Atlantic is consistently greater than $ E-P-R $ over the Pacific by about 0.4 Sv (1 Sv $ \equiv 10^6\; $m$ ^3 $ s$ ^{-1} $). The Atlantic/Pacific $ E-P-R $ asymmetry is found at all latitudes between 30$ ^\circ $S and 60$ ^\circ $N. Further analysis with ERA-Interim combined with a run-off data-set demonstrates that the basin $ E-P-R $ asymmetry is dominated by an evaporation asymmetry in the northern high-latitudes, but by a precipitation asymmetry everywhere south of 30$ ^\circ $N. At the basin scale, the excess of precipitation over the Pacific compared to the Atlantic ($ \sim 30^\circ $S $ - 60^\circ $N) dominates the asymmetry. Also it is shown that the asymmetry is present throughout the year and quite steady from year to year. Investigation of the interannual variability and trends suggest that the precipitation trends are not robust between data-sets and are indistinguishable from variability. However, a positive trend in evaporation (comparable to other published estimates) is seen in ERA-Interim, consistent with sea surface temperature increases. |
format |
Article in Journal/Newspaper |
author |
Philip M. Craig David Ferreira John Methven |
author_facet |
Philip M. Craig David Ferreira John Methven |
author_sort |
Philip M. Craig |
title |
The contrast between Atlantic and Pacific surface water fluxes |
title_short |
The contrast between Atlantic and Pacific surface water fluxes |
title_full |
The contrast between Atlantic and Pacific surface water fluxes |
title_fullStr |
The contrast between Atlantic and Pacific surface water fluxes |
title_full_unstemmed |
The contrast between Atlantic and Pacific surface water fluxes |
title_sort |
contrast between atlantic and pacific surface water fluxes |
publisher |
Stockholm University Press |
publishDate |
2017 |
url |
https://doi.org/10.1080/16000870.2017.1330454 https://doaj.org/article/2a4b20a685554343a2c9a228915eaf81 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Tellus: Series A, Dynamic Meteorology and Oceanography, Vol 69, Iss 1 (2017) |
op_relation |
http://dx.doi.org/10.1080/16000870.2017.1330454 https://doaj.org/toc/1600-0870 1600-0870 doi:10.1080/16000870.2017.1330454 https://doaj.org/article/2a4b20a685554343a2c9a228915eaf81 |
op_doi |
https://doi.org/10.1080/16000870.2017.1330454 |
container_title |
Tellus A: Dynamic Meteorology and Oceanography |
container_volume |
69 |
container_issue |
1 |
container_start_page |
1330454 |
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1766135028085948416 |